Researchers watched 124 kids, ages 2 to 10, and their adult companions as they crossed a parking lot at a community recreation center.
The team found that 67% of the children lacked adult supervision at some point during the walk and nearly 90% were beyond an adult's arm reach.
More than half of kids got out of the vehicle before an adult, according to the University of Alabama at Birmingham study. It was published recently in the Journal of Safety Research.
"Children are unpredictable," study author and associate dean for research David Schwebel said in a university news release. "The safety risks in parking lots are already dangerous. We observed that parents pay less attention to their children in these parking lots, even further elevating the risk."
Every year in the United States, vehicle-pedestrian accidents in places such as parking lots, driveways and on private property cause about 5,000 injuries and 205 deaths among kids 14 years and younger, according to a U.S. National Highway Traffic Safety Administration report.
Study co-author Jenni Rouse, a doctoral student in psychology, said adults and children may overlook the high level of danger in parking lots because vehicles are moving slowly. But she said drivers may not be paying close attention due to distractions such as cellphones, so pedestrians must be extra-vigilant.
"As adult supervisors, we are responsible for teaching children basic pedestrian safety practices and leading by example," Rouse said in the release.
She recommended that adults hold a child's hand in parking lots; make sure kids remain in the car until an adult opens the door; have children exit from the passenger side when being dropped off near a building; and limit distractions as kids are guided through a parking lot, including cellphones and talking with others.
Adults should also teach children to look both ways for traffic before crossing the parking lot; make them aware of the dangers of moving vehicles, and to use sidewalks when available.